Piston for engine-cylinders



Patented Aug. 23,1921;

C. A. MARIEN.

PISTON FOR ENGINE CYLINDERS. APP/LICATION FILED OCT- 29, I92O- I ar/e351flarzn/ jects sought is to make use of pistons cast" its alloys)eflicient' of expansion, so that an ordinary.

UNITED STATES CHARLES A. MARIEN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO H.86 H. MACHINE CO]!!- PANY, OF ST. LOUIS, MISSOURI, A CORPORATION OFMISSOURI.

PISTON FOR ENGINE-CYLINDERS.

Specification of Letters Patent. Patented Aug, 23, 1921;

Application filed October 29, 1920. Serial No. 420,360.

To all whom it may concern}- Be it known that I, CHARLES A. MARIEN, acitizen of the United States, residing at St. Louis, State of Missouri,have invented certain new and useful Improvements in Pistons for-Engine-Cylinders, of which the following is a full, clear, and exactdescription, reference being had to the accompany-' ing drawings,forming a part hereof.

The present invention is directed to improvements in pistonconstruction, and particularly to pistons intended for pse in internalcombustion engines. One of the obfrom aluminum or its alloys to securelightness, and at the same time secure a fit between the piston andwalls of the cylinder that will not only arrest or prevent sideslappingof the piston but will insure against the passage of any oil past thepiston into the combustion chamber of the engine. .As'

well understood in the art, aluminum (and has a comparatively highcoaluminum pitson in an internal combustion engine must when cold, fitwith considerable looseness in the cylinder to allow for subsequentexpansion by the heat of the gases to which the piston is exposed whilethe engine is running. When operating at a high temperature (as a resultof high speed) the piston by reason of expansion may of course maintainproper contact with the walls of the cylinder; but when the temperaturedrops (as when running at low speed) the contraction of the pistonallows so much clearance between it and the cylinder walls as not onlyto cause side-slapping, but at the same time permit aflow of oil pastthe piston (and packing rings) into the combustion chamber and thus giverise to engine trouble. Onthe other hand, if an aluminum piston has thedesired fit when cold, it will bind against and cut or score thecylinder walls when heated, and thus interfere with the free operationof the engine. With my improvement I not only avoid side-slapping of thepiston but insure against the passage of oil into the combustion chamberunder all working conditions by providing the skirt of the piston with aseries of longitudinal 'slits' and resilient skirt sections between theslits, said resilient sections being maintained in permanent and properworking engagement with the cylinder walls by the outward spring of themetal, the necessary rigidity belng imparted tothe skirt by a series oflongitudinally slit tubular metallic filler strlps inserted intosuitable cylindrical enlargements of the slits of the skirt, said stripspermitting the skirt to. expand and PATENT. OFFICE.

contract both radially and circumferentially with any changes oftemperature to which the piston is subjected. The advantages of myimprovement will be fully apparent from the following detaileddescription in connection with the accompanying drawings in which-- 4Figure 1 represents a middle longitudinal section through the cylinderand crank case of an internal combustion engine, showing my inventionapplied thereto; Fig. 2 is ahalf elevation and half middle longitudinalsection of a piston showing the invention on a larger scale; Fig. 3 isan end view of the piston on the side facing the crank-case; Fig.

4 is a longitudinal sectional detail on theline 4-et of Fig. 8; Fig. 5is an enlarged cross-sectional detail on the line 55 of Fig. 2; and Fig.6 is -a perspective of one of the resilient split filler tubes detached.

. Referring to the drawings, C, represents the cylinder, C, thecrank-case, P, the piston, and R, the connecting rod coupling the pistonto the crank-arms A, as well understood in the art. The upper portion ofthe piston is provided with any conventional form of packing ring 1(three rings being shown in the present example), the lower portion orskirt of the piston (the portion nearest the crank-case) being providedwith annular peripheral oil-distributing grooves 2 from which lead ducts3 to the interior of the piston to return any excess oil back to thecrank-case. These features I do not claim as they form no part of myinvention, the latter being concerned with the slitting of the skirt andthe manner of imparting rigidity thereto to prevent side-slapping of thepiston. f

v In the form of the invention, as shown, the skirt of the piston isformed with a plurality of longitudinally disposed parallel slits 4(four in the present example), said slits extending from a pointsubstantially opposite the piston in 5 (inserted through the openings 0of tide bosses 6) to the free end of the skirt (Fig; l), the walls ofthe skirt at the slits being reinforced on the inside by ribs 7.- Thewalls of the slits 4 I are formed with the central tubular or cylinsaidenlargements nal edges of the tube adjacent the slit 8 thereof .beingformed with an outwardly turned flange (1 adapted to be received by theslit 4 of the skirt preferably on the side facing the interior of thepiston (Fig. 5), the thickness of said flange (and of-the walls of thefiller tube) being less than, and approximately one-half the width ofthe slit? 4 to allow for the necessary circumferential expansion of theskirt at high temperatures.

ihe filler tube 8 extends substantially the .full length of the slit 4(and its enlargement ,4 and by the natural tendency of the metal ofwhich said tube is formed to spring outward, it hugs the walls of theenlargements 4' when the, piston is in service (Fig. 5). The fillertubes 8 serve to arrest the splashing (from the crank-case) of any oilthrough the slits 4 against'the cylinder walls, and any ,oil that mayfind its way into the tube through the relatively narrow passage betweenthe flan e a and the opposite wall of i the slit by which it is receivedwill simply run down the tub'e and be returned to the crank-case. Theresult is that any objec-i tionable flow of oil past the lubricatingsurfaces of the piston into the combustion chamher is, practicallyeliminated. .The filler I tubes likewise serve to impart rigidity to theskirt sections, thereby insuring a rigid skirt under all workingconditions and preventing side-slapping of the piston.

'In practice, the skirt portion of the piston is cast slightly oversize,that is to say,

.slightlylarger than the bore of the cylinder,

after which the skirt is slit as shown, thereby imparting to the skirtsections between the slits'a resilience which a skirt. without the slitsdoes notpossess. After the skirt has been a slit, the sections areslightly sprung inward and held in this position by a suitable jig orband, and the piston placed in a lathe and turned true and finishedsmooth. on the outside. When the skirt is released, theparts springoutward (dotted lines Fig. 2), so that when the iston is inserted intothe cylinder thQSklIt hugs the walls thereof the. full length of theslits.

ile the skirt sections are free and out- I .wardly sprung, the tubes 8.are inserted into end carrying the. pistonrings the slit enlar ements.4' throughthe' 0 en ends of the slits, the flanges a being pre erably(though not necessarily) passed into' a the portions of, theslits 4 onthe side facing the Interior of the piston (Fig. 5). When the piston isinserted into the cylinder (the 1 bei in: serted first through theend-of the cylmder facing the crank-case, and-pushed toward the endfacing the combustion chamber E), the outwardly sprung skirt sectionsgradulongitudinally ally'close over the filler tubes, causin acontraction or compression thereof against the tension of theiroutwardly sprung walls, the tubes thereby retaining their places in theslits under working conditions, the stiffness of the tubes preventingthe skirt sections from yielding to the point where side slap; pingis'imminent. Obviously, with any rise 1n temperature the skirt sectionswill expand not only radially but circumferentially as Well. The radialcomponent is taken care "of by 'the radial expansion of the walls .ofthe cylinder, and the circumferential component is taken care of by theslits 4, the

available widths of the slits between'the' flanges a and the oppositeWalls of the slits being sufficient to accommodate the -max1 mumcircumferential expansion that the skirt may undergo. When therefore thepiston. with its resilient filler tubes' is once properly fitted intoits cylinder, that fit is in no wise impaired with any rise 1ntemperature, both components of the expansion- Which the skirt undergoesbeing taken care of, the skirt sections at all times maintaining theirrigidity as a result of the support the same derive from the metallictubular .fillers 8. The pressure of the skirt sections against the wallsof the cylinder is such that while the necessary quantity of oil 1spermitted to flow or pass between the piston and cylinder walls formaintaining the desired lubrication. of the rubbing surfaces, noappreciable quantity of lubricant can find its way past the piston intothe combustion chamber. E. The rigid filler tubes 8 not only prevent anymaterlal yielding of the skirt sections with the diagonal pulls andthrusts of the connecting rod R during the rotation of the crank-shaft,but adjust themselves by their resilience to the expansions andcontractions which the skirt sections undergo with changes oftemperature, the pressure of. the skirt ,against the walls of thecylinder remaining, substantially uniform under all working conditions.The slits 4 while hereshown as parallel to the axis of the piston mayobviously be slightly inclined thereto without involving a departurefrom 115 the nature or spirit of the invention.

Having described my invention what I claim is:

1. A piston for engine cylinders provided Witha skirt slit or dividedlongitudinally, and longitudinally slit filler tubesin the slits of theskirt. V

2. A piston for engine cylinders provided with one or more longitudinalslits open at the free end of the skirt of the piston, and

slit resilient filler. tubes deposited in the slits of the skirt.

3. A piston for engine cylinders provided with a longitudinally slitskirt, 'the slits being open at the free end of the skirt, and suitablefiller tubes mounted in the slits.

4. A piston for engine cylinders provided with a longitudinally slitskirt, the slits being open at the free end of the skirt, and

tions between successive slits, and resilient longitudinally slit fillertubes inserted in said skirt slits.

6. A piston for engine cylinders provided" with a skirt slitlongltudina-lly and forming resilient outwardly springing members orsections between successive slits, the slits be ing formed wit-h centraltubular or cylindrical enlargements, suitable longitudinally slitresilient filler tubes inserted in said enlargements, and outwardlyturned flanges disposed along one of the longitudinal edges of the tubesadjacent the slits thereof received by the slits of the skirt at pointsoutside of and adjacent to the enlargements, said flanges being of lessthickness than the widths of the slits by which they are received.

7. A piston for engine cylinders provided with a skirt slitlongitudinally and forming resilient outwardly springing sectionsbetween successive slits, the slits being formed with medial tubularenlargements, longitudinally slit resilient metallic filler tubes inserted in said enlargements, and outwardly turned flanges disposed alongone of the .edgesof the tubes adjacent the slits thereof received by theslits of the skirt at points outside of and adjacent to the enlargementsand facin the inside of the piston, said flanges belng of less thicknessthan the widths of the slits by which they are received to allow for thenecessary circumferential expansion of the skirt sections.

In testim'ony whereof I afiix my signature, in presence of twowitnesses.

CHARLES A. MAR-IEN.

Vitnesses: EMIL STAREK, ELSE M. SIEGEL.

